Date   

Re: Tek 11000 Series Scope

Steve Wiseman
 

I'm an addict - 11302, 11302A and two broken DSA602s - the 11302s are my
daily drivers, and the DSA602s were, too. Now I have a DSA70604 for all my
high speed storage needs, but I do miss plugins!
I really don't think the power supplies in these things like 240V, as I've
had to replace too many (and don't have a good track record on repairs).
New lab has a massive 240V->110V power conditioner so they'll feel at home
and not blow up so much.

Steve


Re: 2445B with a problem

John Parkins G8KVP
 

Hello Chuck,

I don't get the 02 Test Fail 53 at startup. If I go into the testing
it sometimes fails other times it doesn't, if I leave it looping it
never shows a failure.

As I said the caps on the A5 board looked fine but I stripped them off
along with the resistors and had a really good look at the board under
a microscope. Couldn't see any damage but cleaned it with IPA and gave
the area a good scrub. I'll give it another going over though.
One of the resistors was not showing the correct value, but can't now
remember which one. After they were replaced though I set the DAC as
per the manual.

Would a stuck delta t button be causing this problem though, once on the
cursors aren't coming and going on the display. Seems more like a
sequencing problem U650 or blanking U950.

Tuesday, June 16, 2020, 12:51:31 PM, you wrote:

CH> The Delta t switch is read by the CPU. If the CPU says it is
CH> stuck, it is stuck. Check out the path from the switch to the
CH> CPU. There is a twisty turney path through some opamps, and
CH> MUXes that must work for the test on Delta t to work.

CH> Also, did you scrub the A5 board with hot water and dish detergent?

CH> If not, now is the time. Capacitor electrolyte is highly conductive.

CH> -Chuck Harris

CH> John Parkins G8KVP wrote:
Hello TekScopes,

Posted about this a while ago, but while some work has been done,
nothing has improved this problem. If you'd like to see a video.....

https://youtu.be/nyFnwWyP6XU

Shows the problem. The scope was working perfectly, then I noticed
this happening. Checked out the supply which had been re-capped and
all the voltages, ripple etc are well within spec. While I was in
there I have taken the opportunity to replace the Dallas chip with a
FM1608 having saved the contents and programmed them onto the
FM1608.

The normal problem caps on the A5 board didn't look like they had
been changed, so they have been now. I also found I couldn't get the
required 2.5 v swing on the U2102 DAC so I changed out all the
resistors in that area and now I can. Couldn't see any damage on the
board though.

I can get one error Test 02 Fail 53 which tells me the delta t
switch is stuck, it isn't.

Also noticed that the display is not as sharp as it was.

So any pointers will be gratefully received.
CH>




--
Best regards,
John mailto:john@g8kvp.com


Re: Scope carts

bobkrassa
 

Yes, buying a Tek cart locally is best. But shipping by Trailways or Greyhound is an option - no packaging was required, just a tag, and they handled them well. Inquire if there is a Trailways or Greyhound depot near both you and the seller, and of course ask if they still allow shipping without being in a box.

Bob Krassa ACØJL


Re: 2445B with a problem

Chuck Harris
 

The Delta t switch is read by the CPU. If the CPU says it is
stuck, it is stuck. Check out the path from the switch to the
CPU. There is a twisty turney path through some opamps, and
MUXes that must work for the test on Delta t to work.

Also, did you scrub the A5 board with hot water and dish detergent?

If not, now is the time. Capacitor electrolyte is highly conductive.

-Chuck Harris

John Parkins G8KVP wrote:

Hello TekScopes,

Posted about this a while ago, but while some work has been done,
nothing has improved this problem. If you'd like to see a video.....

https://youtu.be/nyFnwWyP6XU

Shows the problem. The scope was working perfectly, then I noticed
this happening. Checked out the supply which had been re-capped and
all the voltages, ripple etc are well within spec. While I was in
there I have taken the opportunity to replace the Dallas chip with a
FM1608 having saved the contents and programmed them onto the
FM1608.

The normal problem caps on the A5 board didn't look like they had
been changed, so they have been now. I also found I couldn't get the
required 2.5 v swing on the U2102 DAC so I changed out all the
resistors in that area and now I can. Couldn't see any damage on the
board though.

I can get one error Test 02 Fail 53 which tells me the delta t
switch is stuck, it isn't.

Also noticed that the display is not as sharp as it was.

So any pointers will be gratefully received.


2445B with a problem

John Parkins G8KVP
 

Hello TekScopes,

Posted about this a while ago, but while some work has been done,
nothing has improved this problem. If you'd like to see a video.....

https://youtu.be/nyFnwWyP6XU

Shows the problem. The scope was working perfectly, then I noticed
this happening. Checked out the supply which had been re-capped and
all the voltages, ripple etc are well within spec. While I was in
there I have taken the opportunity to replace the Dallas chip with a
FM1608 having saved the contents and programmed them onto the
FM1608.

The normal problem caps on the A5 board didn't look like they had
been changed, so they have been now. I also found I couldn't get the
required 2.5 v swing on the U2102 DAC so I changed out all the
resistors in that area and now I can. Couldn't see any damage on the
board though.

I can get one error Test 02 Fail 53 which tells me the delta t
switch is stuck, it isn't.

Also noticed that the display is not as sharp as it was.

So any pointers will be gratefully received.

--
Best regards,
John mailto:john@g8kvp.com


Does anyone know Donald Rea

 

If anyone knows Donald Rea can they contact me off list at dennis at
ridesoft dot com.
I have an incorrect address for him in Mt Angel OR and I would like to
correct it.
Thank you,
Dennis Tillman W7pF


Re: Encouraging beginners: What are we accomplishing?

Roy Thistle
 

On Sun, Jun 14, 2020 at 11:46 AM, Lawrance A. Schneider wrote:


keeping a 'Tek Scope Usage' group to Tek only
For Tesla coils to nuts there is the EEVblog Forum. If you enjoy separating the wheat from the chaff that's the place to go for lots of chaff.
For LeCroy, Phillips, Fluke, HP, Rigol, et. al. there are groups already... mileage may vary... and if one just wants to wax on about no particular brand, or kind, of oscilloscope the EEVblog Forum has thousands of oscilloscope threads to jump into and post. And there are many other forums for that too.
Forums with coherent and knowledgeable posts about classic Tektronix oscilloscopes.... not so much.


Re: Encouraging beginners: What are we accomplishing?

Roy Thistle
 

On Sun, Jun 14, 2020 at 05:03 PM, petertech99h wrote:


A rising tide floats all boats
Perhaps.
But given a fixed signal level, a rising noise level, lowers the signal to noise ratio, and may prevent the successful transmission of information.
Almost 1/5 the posts on TekScopes mention the term "capacitor."


Re: DSA 602 "partial enhanced accuracy" at each startup

Tom Norman
 

"Would the module throw an error message if its Dallas-chip-battery is gone? "

The 11A34 extended service manual indicates that if the U801 "dallas" chip battery is failing, the plugin will generate a "CKSM Plug" failure. It goes on to note that "In firmware versions of 3.4 or greater, the CKSM Plug diagnostic is not run as a power-up self-test, but is run to decide whether Enhanced Accuracy status has been retained".

I do not know for certain, but I suppose it might be possible that failing the CKSM Plug test request from the mainframe in firmware 3.4, could trigger a partial EA at startup. Your 11A34 is F3.3, so this doesn't seem to be your issue, as it sounds like it would report this as a self test error. I don't think there is extended service info for the 11A33 and 11A72, so uncertain if there is a similar FW difference for those amplifiers.

Have you tried installing only one amp at a time to see if you get the same results of a partial EA at startup (after the initial partial EA due to the reconfiguration)?

Also, as an additional data point, my DSA has FW 2.23, and doesn't have the issue you describe. It has however done a spurious "TekSecure" erase 2 or 3 times in the last 5 years or so.

Tom


Re: A Drop-In Replacement for the U800 (2400 scopes)

victor.silva
 

Ram,

I would love to get one of your U800 modules when you release the final version.
I would be happy to independently evaluate it and post the results here.

Thanks,
Victor


Re: Switching a Tek TDS 5204 to 50 Ohms input impedance - Strange!

Brian
 

Hi Raymond , I have several 7A19's and so far not blown one of the input fuses , I hope I dont ever as I gather that they are rather hard to find , fortunately all the 7A19's I have purchased have had intact fuses and came complete with the spare ones inside if memory serves me well . I've not had that much luck with 7A29's , even with ones that still function , the input attenuator is often damaged such that the input inpedance is no longer constant when changing sensitivity . Fortunately my 7A29P that I purchased for my 7912AD doesnt suffer from that .
I am not 100% sure that the TDS series would exactly follow that original observation but I feel certain that it would in order to protect the input termination , its the only way that gives best protection for it . Later instruments are always more expensive so I would expect the cost of repairing the input termination out of warranty to match the cost of a new instrument . For a modest TDS744 diy replacement of the input hybrid costs in the region of 100GBP , without labour or factory overheads , if they would still do it -- imagine the likely cost if TEK did it


Brian

On Monday, 15 June 2020, 23:45:45 BST, Raymond Domp Frank <hewpatek@gmail.com> wrote:

On Tue, Jun 16, 2020 at 12:27 AM, Brian wrote:


Hi Raymond , I have a couple of TDS's , a 744 original version and a 420A .
Both are protected on the 50R input setting so I would expect all others to be
the same . I have noticed this behaviour when using the 50R input and until I
got used to it having wondered what was happening at first I much prefer it to
the action taken by the 7A29 7k plug-in which just disconnects the input - and
you need to disconnect to reset it.Regrettably I am just a hobbyist pensioner
nowadays so my experience with anything newer than a TDS744 is zero , give me
500 series or 7K series even a 661 and I am happy
Brian Skilton
Hi Brian,
I have had several TDS 4xx and 5xx 'scopes and never experienced this behavior. I'm *that* careful - or lucky...
Nowadays, my only 'scope in that range is a TDS3054 (actually, a modified TDS3032) and I've never tried...
The 7A19 blows an input fuse if overloaded, the 7A29's behavior is much more user-friendly, being resettable.
I love 7K mainframes and I would never think "*regrettably*, I'm a hobbyist pensioner"...
Of course, some things can only be done with the newer stuff but I'm quite happy improvising.

Raymond


Re: Switching a Tek TDS 5204 to 50 Ohms input impedance - Strange!

 

On Tue, Jun 16, 2020 at 12:27 AM, Brian wrote:


Hi Raymond , I have a couple of TDS's , a 744 original version and a 420A .
Both are protected on the 50R input setting so I would expect all others to be
the same . I have noticed this behaviour when using the 50R input and until I
got used to it having wondered what was happening at first I much prefer it to
the action taken by the 7A29 7k plug-in which just disconnects the input - and
you need to disconnect to reset it.Regrettably I am just a hobbyist pensioner
nowadays so my experience with anything newer than a TDS744 is zero , give me
500 series or 7K series even a 661 and I am happy
Brian Skilton
Hi Brian,
I have had several TDS 4xx and 5xx 'scopes and never experienced this behavior. I'm *that* careful - or lucky...
Nowadays, my only 'scope in that range is a TDS3054 (actually, a modified TDS3032) and I've never tried...
The 7A19 blows an input fuse if overloaded, the 7A29's behavior is much more user-friendly, being resettable.
I love 7K mainframes and I would never think "*regrettably*, I'm a hobbyist pensioner"...
Of course, some things can only be done with the newer stuff but I'm quite happy improvising.

Raymond


Re: Switching a Tek TDS 5204 to 50 Ohms input impedance - Strange!

Brian
 

Hi Raymond , I have a couple of TDS's , a 744 original version and a 420A . Both are protected on the 50R input setting so I would expect all others to be the same . I have noticed this behaviour when using the 50R input and until I got used to it having wondered what was happening at first I much prefer it to the action taken by the 7A29 7k plug-in which just disconnects the input - and you need to disconnect to reset it.Regrettably I am just a hobbyist pensioner nowadays so my experience with anything newer than a TDS744 is zero , give me 500 series or 7K series even a 661 and I am happy
Brian Skilton

On Monday, 15 June 2020, 23:04:51 BST, Raymond Domp Frank <hewpatek@gmail.com> wrote:

On Mon, Jun 15, 2020 at 04:27 PM, Brian wrote:


Hi , sorry to but in but I think Tek have got it right . The scope has no idea
if the voltage measured is from a hi-impedance current limited source or a
low-impedance constant voltage source with little or no current limit . The
50R termination in the scope is expensive and difficult / costly to repair so
they play safe to protect it . I would not be complaining about that .
regardsBrian Skilton
These were my thoughts exactly. I wanted to add that the 50 Ohm input may be protected but for a fast 'scope, the circuits would be tiny, so difficult to fully protect. Unfortunately, I couldn't find (the BW of) a TDS 5204 so decided not to write my reaction. Probably an MSO5204?

On Sun, Jun 14, 2020 at 06:26 PM, Jokken Feldhaar wrote:

Did the  engineers at Tek really commit this big time error? I cannot believe this!
So, not an error at all, just clever design!

Raymond


Re: Tek 11000 Series Scope

Reginald Beardsley
 

I use my 11801 a *lot*, particularly with an SD-24 for testing RF connectors and cables.

I missed a chance at an 11801C, but am continuing to look for one.

Reg


Re: Switching a Tek TDS 5204 to 50 Ohms input impedance - Strange!

 

On Mon, Jun 15, 2020 at 04:27 PM, Brian wrote:


Hi , sorry to but in but I think Tek have got it right . The scope has no idea
if the voltage measured is from a hi-impedance current limited source or a
low-impedance constant voltage source with little or no current limit . The
50R termination in the scope is expensive and difficult / costly to repair so
they play safe to protect it . I would not be complaining about that .
regardsBrian Skilton
These were my thoughts exactly. I wanted to add that the 50 Ohm input may be protected but for a fast 'scope, the circuits would be tiny, so difficult to fully protect. Unfortunately, I couldn't find (the BW of) a TDS 5204 so decided not to write my reaction. Probably an MSO5204?

On Sun, Jun 14, 2020 at 06:26 PM, Jokken Feldhaar wrote:

Did the engineers at Tek really commit this big time error? I cannot believe this!
So, not an error at all, just clever design!

Raymond


Re: Some interesting Nuvistor information

Renée
 

mine are in early Tek 422 inputs 8056 and  one 8393 vert amp total of 3
Renée

On 6/15/20 9:44 AM, Dale H. Cook wrote:
On 6/15/2020 12:21 PM, Roy Thistle wrote:

Where any of these used in Tek stuff?
Six 8393s were used in the original release of the Tek 453 in the inputs to both channels and in both trigger generators and both sweep generators. All six were replaced by FETs in the second version of the 453 (serials above 20,000). When Tek introduced the 453 in response to IBM's need for a compact and durable lab-grade 'scope that would fit under an airliner seat the 8393 was a superb choice. Many of us consider the 453 to be the first truly portable lab-grade 'scope.


Re: Scope carts

David Hallam
 

I have a Tek mobile scope cart model 3 in my storage unit.  It's in fairly nice condition, needs to be wiped down to remove accumulate dust and dirt.  After paying for 2 years of storage on the the unit, things have to go.  I will give it to anyone who will come and pick it up, Clearwater, FL.  Otherwise, it goes to the dump.

dchallam@protonmail.com

David
KW4DH

On 6/13/2020 9:14 AM, robert Johnson via groups.io wrote:
For my scope cart I bought a cart from Ikea they are available else where
Utility cart, white, 13 3/4x17 3/4x30 3/4 "

On Saturday, June 13, 2020, 08:49:50 AM EDT, NigelP <nigel-pritchard@outlook.com> wrote:
Carts not easy to come by in the UK. Here's one I made earlier (photos in Albums/Homemade Scope Cart). Made from aluminium alloy rectangular section and MDF, it's vaguely modelled on one of the Tek designs and has a 7904A on top and two TM504s under-slung. The mainframe platform tilts a few degrees, the TM shelf is fixed. There's an MDF drawer compartment that forms the core of the support at the bottom and this holds the probes etc. There's a power distribution board recessed into the back of the drawer compartment.

Also lurking down there is a Tek viewing hood; it's an odd brown colour; I always thought they were blue!

Also in view is the LED inspection lamp so I can actually see the TM504 dials!! Another shot shows the 7603/7L14/TR502 set up plus a small selection of the homemade gear.

Regards

Nigel G8AYM




Re: Some interesting Nuvistor information

Dave Wise
 

No, but early production (ca. 1965) of the Keithley 147 and 148 Nanovoltmeters used a couple of Raytheon CK512AX in the front end.
At the time, they were quieter than semiconductors.

I have a 453, 1A1, 1A2, 1A7, 1S1, and 321A with Nuvistors. One (in the 1A7) was bad when I got it, but I've never had one fail.

Dave Wise
________________________________________
From: TekScopes@groups.io <TekScopes@groups.io> on behalf of Roy Thistle via groups.io <roy.thistle=mail.utoronto.ca@groups.io>
Sent: Monday, June 15, 2020 9:21 AM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Some interesting Nuvistor information

There were manufactured, previous to the Nuvistor, small/miniature, glass jacketed, triodes. These were very rugged. Where any of these used in Tek stuff?


Re: Some interesting Nuvistor information

stevenhorii
 

The mention of Nuvistors in the 1A1 reminded me. I had a 1A1 that had a bad
channel. I got at a hamfest and did not look carefully at it before
plugging it in the scope (a 547) and one channel was dead - the other was
fine. I pulled it and looked more carefully. One of those Nuvistors was
missing. I don't remember how I got a replacement, but when I got it, I put
it in place and the plug in worked fine.

I bought a surplus image converter of some sort. That thing must have
thirty of those miniature glass tubes in it. Probably early '60s vintage.

Steve H

On Mon, Jun 15, 2020, 12:21 Roy Thistle <roy.thistle@mail.utoronto.ca>
wrote:

On Sun, Jun 14, 2020 at 07:45 PM, stevenhorii wrote:


Some details on the Nuvistor
Yes, see George M. Rose Jr.'s 1961 patent, which was called an "electron
tube"... which it was and is... a unique (at least to the U.S. Patent
Office) miniature version of once relatively common metal tubes.... like,
6J5.

https://patentimages.storage.googleapis.com/be/13/ad/774a8fcb959598/US3004185.pdf

Wikipedia says RCA announced the device in 1959. RCA employing their usual
marketing wank... gave it the name Nuvistor: thus forever confusing those
who won't differentiate between conduction in a semiconductor, from
promotion of free electrons via thermal excitation... and conduction in a
vacuum, from promotion of free electrons via thermionic emission.

There were manufactured, previous to the Nuvistor, small/miniature, glass
jacketed, triodes. These were very rugged. Where any of these used in Tek
stuff?




Re: Some interesting Nuvistor information

Paul Amaranth
 

On Mon, Jun 15, 2020 at 11:52 AM, Paul Amaranth wrote:


I have a 453 and a 464 with nuvistors. Never had to replace them although
I do have some spares (somewhere).
Oops, typo, that should be 454 of course

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